Metagenics made a name for itself as a prescription-style supplement company that offered high-potency supplements that were only available with a code from a doctor, chiropractor, or other medical professional.

Now, however, it’s possible to buy them directly online. Does the quality still measure up?

Their magnesium supplement offering comes in the form of magnesium glycinate, a salt form of magnesium that’s not as well-absorbed as a chelate, but tends to be better tolerated than magnesium oxide (used in inexpensive magnesium supplements), which can upset the stomach because of its alkalinity.

The dosage is a fairly standard 100 mg per tablet, and the inactive ingredients are almost identical to a number of its competitors—cellulose, croscarmellose sodium, stearic acid, etc.

Its air of exclusivity still makes it a bit more costly than other competitors, so the value in terms of dollars per serving of magnesium is not as good.

Regardless, it does quite well on independent analytical tests of its contents. Lab testing reveals that it contains 105 mg of magnesium per capsule, meaning there’s an excess of 5% magnesium in your favor.

Accuracy on this order of magnitude is good news if you’re worried about the overall quality of the product.

The magnesium supplement from Life Extension takes a hard-core approach to the absorption challenge—it attempts to hit your body with as many forms of magnesium as possible to maximize the absorption.

The per-capsule dosage is also very high. Each vegetarian capsule contains 500 mg of magnesium (125% of your recommended daily intake), and it comes in four different forms.

These forms include magnesium oxide, magnesium citrate, magnesium succinate, and an amino acid chelate. The thinking behind this unusual approach is to take advantage of different absorption pathways.

While the magnesium oxide waits to be dissolved by your stomach acid before being absorbed, the magnesium amino acid chelate can be absorbed right away—or so the logic goes. It goes without saying that there’s no independent peer-reviewed science on whether this kind of approach actually works.

Regardless, if you know you need to dramatically boost your magnesium intake, Life Extension Magnesium Caps are probably your best choice.

Their magnesium content is within 4% of the label stated amount, and though the cost per serving of magnesium is higher than average (presumably because of the numerous magnesium containing ingredients), its raw power when it comes to delivering a lot of magnesium is tough to beat.

It’s the best selling magnesium supplement on Amazon.com for good reason—Doctor’s Best High Absorption Magnesium provides a reliable dose of magnesium in each tablet.

The tablets themselves contain 100 mg of magnesium each, which represents 25% of your recommended daily intake. If you’re wondering why this amount isn’t higher, it has to do with your body’s magnesium absorption mechanism.

There are diminishing returns associated with higher doses of magnesium—if you take 100% of your daily intake all at once, you won’t actually absorb as much compared to taking 25% at four different times throughout the day (1).

The form of the magnesium in Doctor’s Best is chelated magnesium—this means that each magnesium atom is surrounded by organic molecules that are supposed to help your intestinal tract absorb the magnesium more readily.

Putting the magnesium in a chelate form helps it get absorbed more readily than if it was in a simple inorganic salt form (2).

Aside from the active ingredients, Doctor’s Best contains cellulose and two stearate sources to help bind the tablets together, as well as a compound called croscarmellose sodium—it sounds complex, but really it’s just a powder that allows the tablet to break down more quickly.

Again, this is in keeping with the philosophy of maximizing absorption. Though it’s not the most simplistic magnesium supplement on the market, Doctor’s Best is a great choice if the goal is to maximize absorption.

If you want a simple magnesium supplement that comes in an easily-absorbed form, look no further than Viva Labs. Each capsule provides 100 mg of magnesium (25% of your daily intake) in the form of an amino acid chelate.

The specific form is a proprietary formulation called TRAACS, which is used in a couple of other high-quality magnesium supplements, though not always by itself.

The amino acid chelate requires a few more stabilizers in the tablet, so the ingredients also list some unfamiliar compounds like hydroxypropyl cellulose and ascorbyl palmitate, which might be a disincentive if you’re not a fan of ingredients you can’t pronounce.

Still, the value and simplicity of this supplement is attractive. Amino acid chelates aren’t the cheapest way to deliver magnesium, but when you factor in the better absorption (almost twice as much magnesium gets absorbed from a chelate versus a standard inorganic salt), the value becomes more apparent.

Its label-stated amounts are accurate, too—lab testing finds that the true magnesium content is within 4.5% of the stated amount.

The approach taken by Natural Vitality to magnesium supplementation is a little different. Instead of a capsule or tablet, Natural Vitality Natural Calm comes in a powder form that you scoop into a glass of water to drink.

One serving (assuming your teaspoon measuring skills are accurate) delivers 350 mg of magnesium, which represents 87% of your recommended daily intake. Since it’s a powder, however, you can measure out as much as you want.

The magnesium is in the form of magnesium carbonate, alongside citric acid, presumably to boost absorption and give the drink a tart, pleasing taste. Magnesium carbonate, however, is not absorbed as well as some other forms of the mineral.

Strangely, even though Natural Vitality Natural Calm comes in a powder form, it’s on the expensive side when it comes to cost per serving of magnesium.

Usually, powder form supplements are cheaper, since the manufacturers don’t have to worry about pressing the powder into capsules or tablets, which demands extra machinery and ingredients.

Taking the above considerations in mind, it’s hard to rank Natural Vitality too highly, unless you’re looking for something you can mix into a protein shake or smoothie to boost the magnesium content.

Jigsaw Health’s magnesium supplement is more than just a tablet that provides one nutrient. The philosophy behind this product is to provide several ingredients that work together to help magnesium do its job inside your body.

Whether this product is right for you depends entirely on whether you agree with this approach.

In addition to 125 mg of magnesium, each tablet of Jigsaw Health w/ SRT provides vitamin C, vitamin B6, folic acid, vitamin B12, and malic acid. The rest of the ingredients are the standard binders and stabilizers you’d expect in any tablet—cellulose, croscarmellose sodium, silicon dioxide, and wax.

While each of these other vitamins and minerals have their own roles in the body, and many interact with magnesium, the real question is whether you need them in addition to magnesium in your own diet.

If your vitamin and nutrient deficiencies are widespread, it may be more productive to work on improving your diet directly instead of supplementing with so many different things at once.

These other ingredients push up the cost of Jigsaw Health Magnesium w/ SRT, but not as much as you’d expect. It’s still competitive with other magnesium supplements on the market.

Though its brand name is usually synonymous with quality supplements, Solgar’s magnesium supplement offering is a real disappointment.

It doesn’t offer anything innovative—its tablets contain 200 mg (50% of your recommended daily intake) of magnesium in the form of magnesium citrate, and have some extraneous ingredients that don’t seem strictly necessary, like titanium dioxide and dicalcium phosphate.

Worse, Solgar Magnesium Citrate also suffers from the presence of arsenic contamination. Given the size and scale of Solgar’s supplement manufacturing operation (not to mention the other brands that also have arsenic presence problems), one should expect that they have the capacity to do analytical testing for heavy metal contamination.

Certainly, other manufacturers have been able to create magnesium supplements without arsenic contamination. One of the most effective ways you can exert pressure to solve this problem is to simply not buy supplements that have traces of arsenic in them!

The well-selling KAL magnesium supplement offers a simple and higher dose of magnesium than other competitors. Each tablet contains 200 mg of magnesium in the form of magnesium glycinate, and the only other ingredients are the usual stabilizing agents.

If your magnesium needs are high, you can absorb more of a higher dose, but 200 mg in a single capsule is pushing the limit a bit—you may end up just excreting some of the magnesium unabsorbed, which hurts the cost-effectiveness of the supplement.

More alarmingly, lab testing revealed that KAL contains high levels of arsenic, a known heavy metal toxin.

Though there seems to be a problem with some magnesium formulations including detectable levels of arsenic, many brands are able to prevent its inclusion in the product without any problems.

This alone should be grounds to look elsewhere; it’s very hard to make up for heavy metal presences when competitors offer a superior product.

Though it’s a top-seller on Amazon.com, Sundown Naturals does not rank highly when it comes to the quality and purity of its ingredients.

Each tablet contains 500 mg of magnesium oxide, which should be a red flag from the start—there’s no way your body can absorb all that magnesium at once, and delivering all of it in the form of magnesium oxide is a good way to upset your stomach.

Magnesium oxide is alkaline, meaning it will react with your stomach acid strongly and upset the balance of acidity until it gets dissolved. This is less of a problem in smaller doses, but taking a large bolus of magnesium oxide like this is not the best idea.

Further, there’s a lot of extraneous ingredients in the tablets. Dicalcium phosphate and titanium dioxide are two inactive ingredients which other manufacturers don’t feel the need to put into their magnesium products, so their presence here is a little puzzling.

The real problem, however, comes from analytical testing by an independent laboratory. Testing uncovered unusually high levels of arsenic, a heavy metal that is toxic to your body.

The levels weren’t high enough to be acutely poisonous, of course, but the mere presence of a toxic heavy metal is a real concern. Given that it’s not a market-topper in quality or in value, it’s best to leave this product on the shelf and look for something else.

Part 2: What role does magnesium play in your body and how can supplementation help you?

When your body does not get enough magnesium, you might have muscle cramps or weakness, fatigue, insomnia, and general malaise.

According to one study, almost half the population of the United States does not get enough magnesium in their diet, so addressing magnesium deficiency should be a priority for many people (3).

Benefits of magnesium supplements

If you get plenty of magnesium in your diet from foods rich in magnesium, like almonds, spinach, cashews, other nuts, and black beans, you probably don’t need a magnesium supplement.

But since these foods are not always cheap or easy to integrate into your normal diet, you might find you need extra magnesium from external sources.

One group of people who can often benefit from magnesium supplementation is older men. One of the classic problems that comes with getting old as a male is decreased testosterone.

This male sex hormone is associated with strength, vigor, energy, and libido, and when levels of testosterone decrease, all of these qualities decrease as well.

You’ve no doubt seen advertisements for prescription drugs offered as a treatment for “low T.” Wouldn’t it be great if you could get similar results without a prescription?

There is some tantalizing evidence that this might be possible with magnesium supplementation. A scientific paper published in 2011 in the International Journal of Andrology by Marcello Maggio and other researchers at the University of Parma in Italy studied the blood magnesium levels in a group of elderly men over age 65 (4).

Maggio and his fellow scientists found that, among their sample of elderly men, lower magnesium levels were strongly correlated with lower levels of testosterone, as well as the muscle-building hormone IGF-1 (insulin-like growth factor 1).

This, combined with the fact that almost half of the American population does not get enough magnesium in their diet, indicates that you might see a boost in testosterone if you start taking a magnesium supplement.

Indeed, further evidence for this hypothesis was presented in a study published in 2010 by researchers in Turkey (5).

Martial arts practitioners took either a magnesium supplement or a placebo supplement over the course of a four week training program; during the study, the researchers tracked the testosterone levels of the subjects.

The researchers found that, as we’d expect, magnesium supplementation increased testosterone levels in the athletes; this increase was compounded by the exercise they did.

This suggests that the testosterone boosting effects of magnesium supplementation are better achieved when combined with a full-body exercise routine—in this case, tae kwon do training.

Beyond improving testosterone levels and their associated benefits (more energy, vigor, muscular strength, etc.), magnesium may also be helpful when it comes to improving sleep quality.

A 2012 study by researchers in Iran found that a daily supplementation regimen of 500 mg of magnesium improved subjective measurements of insomnia in elderly patients (6).

The magnesium supplementation program increased sleep time, decreased early morning awakening, and improved the speed at which the patients fell asleep at night.

Magnesium might also be helpful if you have restless leg syndrome at night. A 1998 study by researchers at Albert Ludwigs University in Germany studied ten patients with restless leg syndrome who underwent a magnesium treatment during a four to six week period (7).

The 500 mg dose of magnesium helped decrease periodic limb movements during sleep by over half. Given that other treatments for restless leg syndrome involve fairly powerful neurological drugs, using a magnesium supplement might be an attractive alternative or adjunctive treatment.

Recommended dose

Though research thus far is limited, most studies use doses of around 500 to 700 mg of magnesium per day. The tae kwon do study discussed earlier used a dose of 10 mg of magnesium per kilogram of body mass—so a 150 pound male would take a dose of 680 mg of magnesium per day.

These by-weight formulas help compensate for the fact that larger people need a larger dose of medication to get the same effect as a smaller person.

Recall that the absorption of magnesium is related to the dose you take. If you tried to take 500 mg of magnesium all at once, your body would not absorb it as well as if you’d split that dose into four or five daily portions (11).

Of course, this doesn’t stop some studies from taking this exact approach—the insomnia study on elderly patients conducted in Iran used a straight 500 mg bolus before bed. In practice, this definitely means that less than the full dosage was absorbed.

Keep in mind that your own needs might be lower if your diet is better than average. Indeed, if your diet is good enough, you probably don’t even need a magnesium supplement.

Side effects of magnesium supplements

As a water-soluble nutrient that’s ubiquitous in many kinds of foods, the human body is well-equipped to tolerate a range of magnesium intakes.

One study reports that slight abdominal pain and nonspecific musculoskeletal pain can occur, but this only occurred with a high dose of magnesium chloride consumed in a fasted condition (i.e. without taking any food) (8).

According to Healthline, excessively high doses of magnesium can cause cramping or nausea (9), and the Mayo Clinic cautions that only people with healthy kidney function should take a magnesium supplement (10).

Some types of magnesium supplements might upset your stomach, since some magnesium salts like magnesium oxide will react with the acid in your stomach.

This can be useful—magnesium oxide is sometimes used as a treatment for indigestion and heartburn for this reason—but if you don’t have these problems, it could disrupt the normal function of your stomach acid.

A citrate or amino acid chelate form of magnesium would be better if you’re worried about this.

Recap

There are two groups of people who will likely benefit most from a magnesium supplement. The first group is older people, especially men, who want to boost their testosterone levels for more energy, vigor, muscular strength, and libido.

The second group is people with sleep disturbances like insomnia or restless leg syndrome. Magnesium might be able to help your body get back to normal and leave you feeling stronger, more energetic, and healthier.

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My name is Bastian M. Dubois and I work as Dietitian in St. Mary Healthcare. My passion includes jogging, cooking, and diets. I provide nutritional services for patients, promote sound eating habits through education, and conduct research. I counsel individuals and groups on nutritional practices designed to prevent disease and promote health.